Hemolytic Disease of the Newborn Flashcards
What is a sign/complication of HDN?
Extramedullary hematopoiesis
Heart and liver failure (leading to edema)
Jaundice
Kernicterus
What is the mechanism for HDN?
Baby inherits Rh antigen from dad
Baby blood goes into mom’s blood
Mom’s blood makes antibodies against baby RBC’s
Mom’s antibodies attack and kill baby RBC’s
What is Kernicterus?
It’s the accumulation of bilirubin in the brain due to an increased permeability of the BBB.
Why is it that the first baby is usually safe from HDN but the second baby isn’t?
The first reaction invokes IgM, which can’t cross the placental barrier
The second exposure invokes IgG which can cross the placenta
What is Rhogam?
An antiimmunoglobulin for D antibodies
How do you diagnose HDN?
DAT for newborn
IAT for mother
What is the Kleihauer-Betke Test?
Take mom’s blood
Expose to acid bath
Stain it
Look at amount of baby RBC’s in comparison to mom’s.
You can tell how much hemorrhage is occurring.
How does flow cytometry work for determining fetal blood in mother’s blood?
Take sample
Give anti-HgF antibody
Run flow
You can tell if there’s HgF and how much there is by how fast the blood runs
Why is ABO rejection uncommon in infants?
Antibody is IgM
Fetal RBC’s express AB poorly
How do you treat mild ABO rejection?
Severe?
Mild: Phototherapy
Severe: Total exchange transfusion
